The stratum corneum is the outer-most layer of the skin and is responsible for regulating skin water levels and functioning as a barrier against chemicals and other stress agents found in the environment. The complex arrangement of lipids in the intercellular space of the stratum corneum is responsible for the establishment of normal barrier function. Multi-layered structures of cholesterol, ceramides and fatty acids, as well as some other minor lipids, provide the major barrier to the transport of substances into or through the skin. The overall structure of the stratum corneum acts as the frontline barrier to the skin. The link between skin barrier function and skin health is apparent from the skin inflammation caused by lipid extraction from the skin. That is, when skin barrier function is impaired, the other layers of the skin can be injured and have a response to that injury in the form of inflammation.
Absorbent articles such as diapers, training pants, incontinence products and feminine care products are worn such that they are in direct contact with the skin of the wearer. An unavoidable consequence of the use of absorbent articles is that the skin is exposed more directly to biological insults. Consequently, the barrier function of the skin covered by the absorbent article is put at risk. Biological fluids, such as urine, may contain a variety of components that can damage the skin barrier. Diaper dermatitis is a genre of skin conditions that, in large part, originate from impaired skin barrier function. Impairment of the skin barrier can result from a variety of factors, including: increased skin hydration due to the occlusion of the skin caused by diapers. Excessive hydration of the skin has a negative effect on the skin barrier. The hydration level of diapered skin, for example, may reach between five to ten times that of undiapered skin. It is believed to be frequent contact of diapered skin with urine contributes to increased skin hydration. Increased skin hydration disrupts skin lipid organization in the stratum corneum. This disruption may increase the permeability of the skin to irritants from feces and urine, thus increasing the risk of skin inflammation.
Disposable absorbent articles such as diapers, training pants, adult incontinence products, absorbent under pants, feminine care products and nursing pads have been used to absorb body fluids and leave the skin dry. Disposable absorbent articles of this type generally include a liquid impermeable outer cover, an absorbent body, and a liquid permeable bodyside liner. The bodyside liner comes into contact with the wearer's skin and is interposed between the skin and the absorbent body. Generally, the bodyside liner is not configured to retain liquid, which passes through the bodyside liner to the absorbent body where it is retained. However, the location of the absorbent body immediately adjacent the bodyside liner can cause the skin to be hydrated by moisture (e.g., urine) which is held in the absorbent body immediately adjacent to the bodyside liner, or at a minimum inhibit adequate ventilation of the skin. The presence of these conditions is believed to be detrimental to skin health.